The 2032 and similar 3V coin cells are a non-rechargable Lithuim chemistry. I used to know what one but can't remember the details right now. I guess we'll have to wait for a future article from Ivan...

> Laptops and their batteries seem to be some of the worst offenders...

My work laptop - a Lenovo T510 which is showing its age in other respects - has a great battery with over 3 hrs life BUT best of all the run time indicator is almost bang on. It is in time (hrs/min) which I reckon is the most useful indication (which answers Duane's question) but switches to % when it is on charge. I have never recalibrated it and it's only a couple of minutes out -if that - at the end of the battery life. I guess I am lucky....

Are the ubiquitous computer memory "coin cells" - 2032 et al - Silver oxide or another chemistry? They are nominally 3V so if Silver Oxide they'd have to be 2 cells in series so I suspect they are something else?

This is really calibrating the measuring system. Is that correct? I've heard about this, but never had it explained clearly.

Some systems that I have list battery capacity as percent remaining. Others list it as time remaining. The challenge with using time as the measuring stick is, of course, that it's dependent upon the specific load.

I've seen some systems that appear to base the time left on the instantaneous load. If I turn up the brightness on the backlight, time left will drop and turning down the backlight does the opposite. Other devices seem to attempt to base the time left on the average consumption from full charge. It would be nice if all the systems were consistent.

The funny thing is that this really isn't a new problem. Every car I've owned has had a different accuracy curve for the gas gauge. It will move slowly for the first half of the gauge, then drop quite fast once indicating below half a tank. The gage does nothing to compensate for the difference in fuel consumption in the city vs. on the highway.

I understand that the car gage is simply attempting to display the quantity, not rage. Eventually, I get an internal sense for range. I kind of do the same with my electronic devices. I calibrate my head.